1. Field of the Invention
The present invention relates to a sample analyzer and a sample analyzing method for analyzing a target substance contained in a sample using a reagent containing magnetic particles.
2. Description of the Related Art
An analyzer for analyzing a target substance contained in a sample using a reagent containing magnetic particles is conventionally known. In such analyzer, the BF (Bound-Free) separating process of separating an immune complex containing the target substance from a unreacted substance is carried out. In the BF separating process, the immune complex in which an analyzing target (antigen or antibody) in the sample and the magnetic particles bound with a reactive substance that specifically binds with the analyzing target are reacted is captured at the inner wall of a reaction container by a magnetic force, and the unreacted substance in the reaction container is removed leaving the immune complex captured at the inner wall of the reaction container by supplying cleaning liquid to the reaction container and aspirating the liquid in the reaction container.
U.S. Patent Publication No. 2008/206099 discloses an analyzer including one magnetism separator, one impurity aspirating mechanism, and one cleaning liquid discharging mechanism, where the BF separating process is carried out by repeating aspiration by the impurity aspirating mechanism and discharge of the cleaning liquid in the reaction container transferred to the magnetism separator.
Japanese Patent Publication No. 2001/91521 discloses an analyzer including a BF separation mechanism with a transferring body for transporting the reaction container, three cleaning ports arranged along the transporting direction of the reaction container by the transferring body, and three BF nozzles, arranged in correspondence with the three cleaning ports, for aspirating the impurities and discharging the cleaning liquid. In such BF separation mechanism, the reaction container is sequentially transported to the three cleaning ports by the transferring body, where the aspiration of the impurities and the discharging of the cleaning liquid are performed two times in each of the three cleaning ports. That is, the BF separating process is completed when the aspiration of the impurities and the discharging of the cleaning liquid are performed for a total of six times on one reaction container when one reaction container passes the three cleaning ports.
However, in the analyzer disclosed in U.S. Patent Publication No. 2008/206099, the BF separating process can be carried out on only one reaction container at once, and hence the BF separating process takes time when processing a great number of reaction containers, and as a result, the sample processing ability of the analyzer becomes difficult to enhance.
Furthermore, in the analyzer disclosed in Japanese Patent Publication No. 2001/91521, the BF nozzle of the cleaning port positioned on the upstream side in the transporting direction of the reaction container is inserted into the specimen of high concentration of the unreacted substance to carry out aspiration and discharge each time, and hence the BF nozzle of the cleaning port on the upstream side is more contaminated than the BF nozzle of the cleaning port on the downstream side. Thus, if only the BF nozzle on the upstream side is cleaned over a long time to prevent occurrence of carry-over of the substance contained in the previous sample to the next sample, the BF separating process cannot be started until the cleaning of the BF nozzle on the upstream side is completed and the sample processing ability of the analyzer becomes difficult to enhance. Furthermore, if the cleaning time is set the same for the BF nozzle on the upstream side and the BF nozzle on the downstream side in view of the processing efficiency, the carry-over to the next sample may occur due to contamination attached to the BF nozzle on the upstream side having high contamination degree.